An integral part of the Grande Maison's heritage, the Jaeger-LeCoultre ultra-thin watch has written some of the most beautiful pages of modern watchmaking, illuminating the 20th century with innovations and exceptional creations. In 1903, the French manufacturer of marine chronometers Edmond Jaeger wished to combine technology with refinement. He chose to focus on the production of ultra-thin watches. Since his workshop did not allow him to machine all the components he required, he turned to Swiss manufacturers. Jacques-David LeCoultre took up the challenge and the two men went into partnership. Together, they created the thinnest calibres in the world. Thus, the Calibre LeCoultre 145, created in 1907 for pocket watches, today remains the thinnest in the world in its category, with a thickness of just 1.38 millimetres. Enriching the tradition of ultra-thin watches so beloved of the Jaeger-LeCoultre Manufacture, the manually wound Calibre 849, created in 1994, measures a mere 1.85 mm in thickness. As for the automatically winding Calibre 896, which is only 3.98 mm in thickness, it equips the Montre Master Ultra Thin Small Second watch.